Human miscarriage and infection in Tunisia: Role of Mycoplasma hominis and high Waddlia seroprevalence

Introduction: Miscarriage is one of the most common adverse pregnancy outcomes. The aim of this study was to investigate the relationship between miscarriage in humans and infections caused by zoonotic bacteria and genital pathogens. Methodology: Cervicovaginal swabs and placenta samples from 132 women with miscarriage (patient group: PG), and cervicovaginal swabs from 54 women with normal pregnancy (control group: CG), were subjected to bacteriological culture and real time PCRs detecting Coxiella burnetii, Brucella spp, Mycoplasma hominis, Mycoplasma genitalium, Ureaplasma urealyticum, Chlamydia trachomatis, Waddlia chondrophila and Parachlamydia acanthamoebeae DNA. Serology of C. burnetii, C. trachomatis and W. chondrophila was also performed. Results: Placenta samples were positive for E. coli, S. agalactiae, U. urealyticum, M. hominis and C. trachomatis in 4.7%, 3.1%, 3.1%, 0.7% and 0.7% of cases, respectively. For cervicovaginal swabs, M. hominis was more frequently detected among PG than CG with a significant statistical difference (p = 0.02). C. trachomatis was detected in 3.3% and 5.5% among PG and CG, respectively. U. urealyticum DNA was detected with high percentages in the two groups. Samples from both groups showed negatives results for C. burnetii, Waddlia, and Brucella qPCRs. A high rate of W. chondrophila seroprevalence (42%) was noted with significant difference among women with early miscarriage. Conclusions: C. trachomatis, S. agalactiae and M. hominis may play a role in miscarriage. However, the full characterization of the vaginal flora using other technologies such as NGS-based metagenomics is needed to clarify their role in miscarriage. Finally, further investigations should be performed to explain high W. chondrophila seroprevalence.